package com.example.demo.filter;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.security.authentication.AuthenticationManager;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.core.authority.SimpleGrantedAuthority;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.security.web.authentication.www.BasicAuthenticationFilter;

import com.example.demo.custom.JwtTokenUtils;
import com.example.demo.security.User2;

public class JWTAuthenticationFilter extends BasicAuthenticationFilter {
	public JWTAuthenticationFilter(AuthenticationManager authenticationManager) {
		super(authenticationManager);
	}

	@Override
	protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain chain)
			throws IOException, ServletException {
		String tokenHeader = request.getHeader(JwtTokenUtils.TOKEN_HEADER);
		// 如果请求头中没有Authorization信息则直接放行了
		if (tokenHeader == null||!tokenHeader.startsWith(JwtTokenUtils.TOKEN_PREFIX)) {
			chain.doFilter(request, response);
			return;
		}
		// 如果请求头中有token，则进行解析，并且设置认证信息
		SecurityContextHolder.getContext().setAuthentication(getAuthentication(tokenHeader));
		// chain.doFilter(request, response);
		super.doFilterInternal(request, response, chain);
	}

	// 这里从token中获取用户信息并新建一个token
	private UsernamePasswordAuthenticationToken getAuthentication(String tokenHeader) {
		String token = tokenHeader.replace(JwtTokenUtils.TOKEN_PREFIX, "");
		String username = JwtTokenUtils.getUsername(token);
		String name = JwtTokenUtils.getName(token);
		String role = JwtTokenUtils.getUserRole(token);
		if (username != null) {
			List<GrantedAuthority> authorities = new ArrayList<>();
			for (String authStr : role.split(",")) {
				authorities.add(new SimpleGrantedAuthority(authStr));
			}
			User2 user = new User2(username, "", name, authorities);
			return new UsernamePasswordAuthenticationToken(user, null, authorities);
		}
		return null;
	}
}
